Electronic device

ABSTRACT

A device is prepared using a chemical vapor deposition method and has a patterned thin film on a substrate that is applied using a deposition inhibitor material. The deposition inhibitor material is a hydrophilic polymer that is a neutralized acid having a pKa of 5 or less, wherein at least 90% of the acid groups are neutralized. The deposition inhibitor material can be patterned simultaneously or subsequently to its application to the substrate, to provide selected areas of the substrate effectively not having the deposition inhibitor material. A thin film is substantially deposited only in the selected areas of the substrate not having the deposition inhibitor material.

RELATED APPLICATION

This is a divisional application of recently allowed, copending, andcommonly assigned U.S. Ser. No. 12/622,506 (filed Nov. 20, 2009).

COPENDING AND COMMONLY ASSIGNED APPLICATIONS

Reference is made to the following copending and commonly assigned U.S.patent application, filed on even date herewith:

-   -   U.S. Ser. No. 12/622,530 filed by myself on Nov. 20, 2009;    -   U.S. Ser. No. 12/622,496 filed by myself on Nov. 20, 2009;    -   U.S. Ser. No. 12/622,519 filed by myself on Nov. 20, 2009;    -   U.S. Ser. No. 12/622,550 filed by myself and Lee W. Tutt on Nov.        20, 2009; and    -   U.S. Ser. No. 12/622,660 filed by myself and Gregory Zwadlo on        Nov. 20, 2009.

FIELD OF THE INVENTION

This invention relates to a method of atomic layer deposition ofmaterials onto a substrate and the use of specific polymers that is aneutralized acid having a pKa of 5 or less, as deposition inhibitormaterials in selective deposition. This invention also relates toelectronic devices prepared using this method.

BACKGROUND OF THE INVENTION

Modern-day electronics require multiple patterned layers of electricallyor optically active materials, sometimes over a relatively largesubstrate. Electronics such radio frequency identification (RFID) tags,photovoltaics, and optical and chemical sensors all require some levelof patterning in their electronic circuitry. Flat panel displays, suchas liquid crystal displays or electroluminescent displays rely uponaccurately patterned sequential layers to form thin film components ofthe backplane. These components include capacitors, transistors, andpower buses. The industry is continually looking for new methods ofmaterials deposition and layer patterning for both performance gains andcost reductions.

Thin film transistors (TFTs) may be viewed as representative of theelectronic and manufacturing issues for many thin film components. TFTsare widely used as switching elements in electronics, for example, inactive-matrix liquid-crystal displays, smart cards, and a variety ofother electronic devices and components thereof. The thin filmtransistor (TFT) is an example of a field effect transistor (FET). Thebest-known example of an FET is the MOSFET(Metal-Oxide-Semiconductor-FET), today's conventional switching elementfor high-speed applications. For applications in which a transistorneeds to be applied to a substrate, a thin film transistor is typicallyused. A critical step in fabricating the thin film transistor involvesthe deposition of a semiconductor onto the substrate. Presently, mostthin film devices are made using vacuum deposited amorphous silicon asthe semiconductor, which is patterned using traditionalphotolithographic methods. Amorphous silicon as a semiconductor for usein TFTs still has its drawbacks. Thus, there has been active work tofind a suitable replacement.

There is a growing interest in depositing thin film semiconductors onplastic or flexible substrates, particularly because these supportswould be more mechanically robust, lighter weight, and allow moreeconomic manufacturing, for example, by allowing roll-to-rollprocessing. A useful example of a flexible substrate is polyethyleneterephthalate. Such plastics, however, limit device processing to below200° C.

In spite of the potential advantages of flexible substrates, there aremany problems associated with plastic supports when using traditionalphotolithography during conventional manufacturing, making it difficultto perform alignments of transistor components across typical substratewidths up to one meter or more. Traditional photolithographic processesand equipment may be seriously impacted by the substrate's maximumprocess temperature, solvent resistance, dimensional stability, water,and solvent swelling, all key parameters in which plastic supports aretypically inferior to glass.

There is interest in utilizing lower cost processes for deposition thatdo not involve the expense associated with vacuum processing andpatterning with photolithography. In typical vacuum processing, a largemetal chamber and sophisticated vacuum pumping systems are required inorder to provide the necessary environment. In typical photolithographicsystems, much of the material deposited in the vacuum chamber isremoved. The deposition and photolithography items have high capitalcosts and preclude the easy use of continuous web based systems.

In the past decade, various materials have received attention as apotential alternative to amorphous silicon for use in semiconductorchannels of thin film transistors. The discovery of practical inorganicsemiconductors as a replacement for current silicon-based technologieshas also been the subject of considerable research efforts. For example,metal oxide semiconductors are known that constitute zinc oxide, indiumoxide, gallium indium zinc oxide, tin oxide, or cadmium oxide depositedwith or without additional doping elements including metals such asaluminum. Such semiconductor materials, which are transparent, can havean additional advantage for certain applications, as discussed below.Additionally, metal oxide dielectrics such as alumina (Al₂O₃) and TiO₂are useful in practical electronics applications as well as opticalapplications such as interference filters.

In addition, metal oxide materials can serve as barrier or encapsulationelements in various electronic devices. These materials also requirepatterning so that a connection can be made to the encapsulated devices.

Although successful thin films in electronic devices have been made withsputtering techniques, it is clear that very precise control over thereactive gas composition (such as oxygen content) is required to producegood quality devices. Chemical vapor deposition (CVD) techniques, inwhich one or more reactive gasses decompose or react to form the desiredfilm material at a surface, can be useful routes to achieving highquality film growth. Atomic layer deposition (“ALD”) is yet analternative film deposition technology that can provide improvedthickness resolution and conformal capabilities, compared to its CVDpredecessor. The ALD process segments the conventional thin-filmdeposition process of conventional CVD into single atomic-layerdeposition steps.

ALD can be used as a fabrication step for forming a number of types ofthin-film electronic devices, including semiconductor devices andsupporting electronic components such as resistors and capacitors,insulators, bus lines, and other conductive structures. ALD isparticularly suited for forming thin layers of metal oxides in thecomponents of electronic devices. General classes of functionalmaterials that can be deposited with ALD include conductors, dielectricsor insulators, and semiconductors. Examples of useful semiconductingmaterials are compound semiconductors such as gallium arsenide, galliumnitride, cadmium sulfide, zinc oxide, and zinc sulfide.

Advantageously, ALD steps are self-terminating and can deposit preciselyone atomic layer when conducted up to or beyond self-terminationexposure times. An atomic layer typically ranges from about 0.1 to about0.5 molecular monolayers with typical dimensions on the order of no morethan a few Angstroms. In ALD, deposition of an atomic layer is theoutcome of a chemical reaction between a reactive molecular precursorand the substrate. In each separate ALD reaction-deposition step, thenet reaction deposits the desired atomic layer and substantiallyeliminates “extra” atoms originally included in the molecular precursor.In its most pure form, ALD involves the adsorption and reaction of eachof the precursors in the complete absence of the other precursor orprecursors of the reaction. In practice in any process it is difficultto avoid some direct reaction of the different precursors leading to asmall amount of chemical vapor deposition reaction. The goal of anyprocess claiming to perform ALD is to obtain device performance andattributes commensurate with an ALD process while recognizing that asmall amount of gas phase nucleation can be tolerated.

In ALD processes, typically two molecular precursors are introduced intothe ALD reactor in separate stages. The details of such stages andmolecular precursors useful in each are explained in [0016]-[0034] ofU.S. Patent Application Publication 2009/0081827 (Yang et al.) that isincorporated herein by reference along with the references mentioned inthese paragraphs.

U.S. Patent Application Publication 2005/0084610 (Selitser) discloses anatmospheric pressure atomic layer chemical vapor deposition process thatinvolve separate chambers for each stage of the process and a series ofseparated injectors are spaced around a rotating circular substrateholder track.

A spatially dependent ALD process can be accomplished with otherapparatus or methods described in more detail in WO 2008/082472 (Cok),U.S. Patent Application Publications 2008/0166884 (Nelson et al.),2008/0166880 (Levy), 2009/0130858 (Levy), 2009/0078204 (Kerr et al.),2009/0051749 (Baker), 2009/0081366 (Kerr et al.), and U.S. Pat. Nos.7,413,982 (Levy), 7,456,429 (Levy), and 7,572,686 (Levy et al.), all ofwhich are hereby incorporated by reference in their entirety. Thesepublications described various attempts to overcome one of the difficultaspects of a spatial ALD system, which is undesired intermixing of thecontinuously flowing mutually reactive gases.

There is growing interest in combining ALD with a technology known asselective area deposition (or “SAD”) in which a material is depositedonly in those areas that are desired or selected. Sinha et al. [J. Vac.Sci. Technol. B 24 6 2523-2532 (2006)] have remarked that selective areaALD requires that designated areas of a surface be masked or “protected”to prevent ALD reactions in those selected areas, thus ensuring that theALD film nucleates and grows only on the desired unmasked regions. It isalso possible to have SAD processes where the selected areas of thesurface area are “activated” or surface modified in such a way that thefilm is deposited only on the activated areas. There are many potentialadvantages to selective area deposition techniques, such as eliminatingan etch process for film patterning, reduction in the number of cleaningsteps required, and patterning of materials which are difficult to etch.One approach to combining patterning and depositing the semiconductor isshown in U.S. Pat. No. 7,160,819 (Conley et al) that describes materialsfor use in patterning zinc oxide on silicon wafers.

A number of materials have been used by researchers as depositioninhibitor materials for selective area deposition. Sinha et al.,referenced above, used poly(methyl methacrylate) (PMMA) in their maskinglayer. Conley et al. employed acetone and deionized water, along withother process contaminants as deposition inhibitor materials.

U.S. Patent Application Publications 2009/0081827 and 2009/0051740 (bothnoted above) describe the use of crosslinkable organic compounds orpolymers, such as organosiloxane polymers, as deposition inhibitormaterials, in ALD processes to provide various electronic devices. Thesecrosslinkable materials are generally coated out of organic solvents.There is a need to avoid the use of organic solvents in providingdeposition inhibitors when fabricating various useful devices usingchemical vapor deposition techniques such as ALD.

The problem with these previously used materials is that they rely uponpolymers that are soluble only in aggressive organic solvents. Asidefrom health and environmental concerns, the use of aggressive organicsolvents is difficult in a large scale manufacturing process. Amongthese disadvantages include: (a) cleanup of coated materials must bedone with similar organic solvents, leading to increased solvent usage,and (b) many of the printing technologies proposed for printedelectronics leverage elastomer printing plates that swell upon contactwith aggressive organic solvents. Therefore, there has been a need forselective deposition inhibitors that are soluble in environmentallyfriendly solvents, principally water and alcohols, and can be applied asaqueous formulations.

SUMMARY OF THE INVENTION

This invention provides an electronic device having a substrate andhaving thereon:

-   -   a deposited pattern of a composition comprising a deposition        inhibitor material, and    -   a deposited inorganic thin film disposed only in selected areas        of the substrate where the composition comprising a deposition        inhibitor material is absent,    -   wherein the deposition inhibitor material is a hydrophilic        polymer that is a neutralized acid having a pKa of 5 or less,        wherein at least 90% of the acid groups are neutralized.

It is an advantage of the present invention that selective deposition ofmetal oxides and other materials can be used in a chemical vapordeposition process such as ALD system, for example a spatially dependentALD system. It is yet a further advantage of the present invention thatit is adaptable for deposition on a web or other moving substrate,including deposition onto a large area substrate. It is another that theinvention allows operation under atmospheric pressure conditions, forexample in low temperature processes at atmospheric pressures in anunsealed environment or open to ambient atmosphere.

The present invention provides for the deposition of a depositioninhibitor material that can be applied in an aqueous medium instead of astrictly organic solvent medium. Thus, this aqueous medium or solutioncomprises at least 50% by weight water.

These advantages are provided by using a unique deposition inhibitormaterial that is a hydrophilic polymer that is a neutralized acid havinga pKa of 5 or less, wherein at least 90% of the acid groups areneutralized, as defined in more detail below.

Other objects, features, and advantages of the present invention willbecome apparent to those skilled in the art upon a reading of thefollowing detailed description when taken in conjunction with thedrawings that show and describe illustrative embodiments of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional side view of a delivery head for atomiclayer deposition for one embodiment of the present invention.

FIG. 2 is a flow chart describing one embodiment of the steps of thepresent invention.

FIG. 3 is a flow chart describing the steps for an ALD process for usein the present invention.

FIG. 4 is a cross-sectional side view of one embodiment of a depositiondevice for atomic layer deposition that can be used in the presentprocess.

FIG. 5 is a cross-sectional side view of an embodiment, for oneexemplary system of gaseous materials, of the distribution of gaseousmaterials to a substrate that is subject to thin film deposition;

FIGS. 6A and 6B are cross-sectional side views of one embodiment of thedistribution of a system of gaseous materials, schematically showing theaccompanying deposition operation;

FIG. 7 is a perspective view, from the output face side, of a portion ofone embodiment of a deposition device, showing the orientation of outputchannels relative to the substrate and reciprocating motion, showing oneexemplary arrangement of gas flow in the deposition device;

FIGS. 8A and 8B are cross-sectional views taken orthogonally to thecross-sectional views of previous FIGS. 4, 5, 6A, and 6B, showing gasflow directions for output channels in various embodiments.

FIG. 9 is a schematic diagram showing an alternative motion pattern forreciprocating and orthogonal movement.

FIG. 10 is a block diagram for one embodiment of a deposition systemthat uses the method according to the present invention.

FIG. 11 is a block diagram showing another embodiment of depositionsystem applied to a moving web in accordance with the present invention,with the deposition device being kept stationary.

FIGS. 12A through 12E show the layers on the substrate at differentpoints in the process in one embodiment of the present invention.

FIGS. 13A through 13D show the layers on the substrate at differentpoints in another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Definitions

As used herein, the term “hydrophilic polymer” refers to a naturallyoccurring or synthetically prepared organic compound having a molecularweight of at least 1,000. This organic compound is soluble in an aqueoussolution comprising 50% water and the rest comprising one or morewater-miscible organic solvents for example alcohols (such as methanol,ethanol, n-propanol, 2-propanol, t-butyl alcohol, glycerin, dipropyleneglycol, ethylene glycol, and polypropylene glycol), ketones (such asacetone and methyl ethyl ketone), glycol ethers (such as ethylene glycolmonomethyl ether, ethylene glycol monoethyl ether, ethylene glycolmonobutyl ether, diethylene glycol monoethyl ether, diethylene glycolmonobutyl ether, diethylene glycol diethyl ether, triethylene glycolmonobutyl ether, and dipropylene glycol monomethyl ether), andwater-soluble nitrogen-containing organic solvents (such as2-pyrrolidone and N-methylpyrrolidone), and ethyl acetate.

Thus, the hydrophilic polymer satisfies both of the following tests:

-   -   a) it is soluble to at least 1% by weight in a solution        containing at least 50 weight % water as measured at 40° C., and    -   b) it provides an inhibition power of at least 200 Å to        deposition of zinc oxide by an ALD process.

The term “deposition inhibitor material” refers herein to a materialapplied to the substrate as well as the material resulting from anyoptionally subsequent crosslinking or other reaction that modifies thematerial that may occur prior to depositing an inorganic thin film onthe substrate using a chemical vapor deposition technique.

For the description that follows, the term “gas” or “gaseous material”is used in a broad sense to encompass any of a range of vaporized orgaseous elements, compounds, or materials. Other terms used herein, suchas: reactant, precursor, vacuum, and inert gas, for example, all havetheir conventional meanings as would be well understood by those skilledin the materials deposition art. The FIGS. provided with thisapplication are not drawn to scale but are intended to show overallfunction and the structural arrangement of some embodiments of thepresent invention.

Deposition Methods

The present invention provides various electronic devices including butnot limited to, integrated circuits, active-matrix displays, solarcells, active-matrix imagers, sensors, and rf labels using a suitablechemical vapor deposition method described herein. Such electronicdevices have a substrate that can be composed of polymeric films (suchas polyethylene terephthalate, polyethylene naphthalate, polyimide,polyetheretherketone (PEEK), or any polymer with suitable temperatureresistance for electronics applications), ceramics, glasses, and metalfoils including aluminum, steel, or stainless steel.

A deposited pattern of a composition that comprises a depositioninhibitor material is applied to the substrate. This compositioncomprises the hydrophilic polymer that is defined below. A depositedinorganic thin film is deposited only in selected areas of the substratewhere the composition comprising a deposition inhibitor material isabsent. Useful thin films are described below.

The composition comprising the deposition inhibitor material can beapplied in a patternwise fashion using any conventional printingtechnology. Particularly useful printing technologies are inkjet,flexography, gravure printing, microcontact printing, offsetlithography, patch coating, screen printing, and donor transfer methods.The deposition inhibitor may also be applied uniformly by any of theabove methods, or by hopper coating, spin coating blade coating, or dipcoating. After uniform coating, the deposition inhibitor can bepatterned by exposure to radiation ranging from infrared to x-ray,mechanical embossing, or removal means, or by localized etching orsurface treatment.

The functional thin film can be applied using a chemical vapordeposition (CVD) method, the general principles of which are describedin many publications including Dobkin et al., Principles of ChemicalVapor Deposition, 1 Edition, April 2003 and the Handbook of ChemicalVapor Deposition 2^(nd) Ed., Second Edition Principles, Technology andApplications (Materials Science and Process Technology Series), Piersonet al., Jan. 14, 2000. Specific types of CVD systems include the use oftube reactions as described in U.S. Pat. No. 6,709,525 (Song),showerhead reactors as described in U.S. Pat. No. 6,284,673 (Dunham),and linear injector reactors as described in U.S. Pat. No. 5,136,975(Bartholomew et al.), all of which publications are incorporated hereinby reference.

While these methods can be used, it is best to carry out the presentinvention using atomic layer deposition (ALD). ALD processes can beunderstood from the background section and various publications citedtherein. Additional teaching about ALD and useful apparatus for carryingout the process is provided in U.S. Pat. Nos. 7,105,054 (Lindfors),7,085,616 (Chin et al.), 7,141,095 (Aitchison et al.), and 6,911,092(Sneh), all of which are incorporated herein by reference.

The present invention employs a deposition inhibitor material describedbelow that inhibits the deposition of the thin films on its surface. Inthis manner, portions of the substrate where there is a depositioninhibitor material will have little to no thin film growth, and in areasof the substrate that are generally free of the deposition inhibitormaterial will have thin film growth.

Useful deposition inhibitor materials include hydrophilic polymershaving a free acid content of less than 2.5 meq/g of polymer and issoluble in an aqueous solution comprises at least 50% of water byweight. These hydrophilic polymers are generally not crosslinked sincethat will likely reduce their water-solubility. However, crosslinkablepolymers may be useful where crosslinking is performed after applicationof the polymer. Crosslinking of the polymer may increase its stabilityespecially in applications where the polymer remains in the constructeddevice.

Useful hydrophilic polymers are neutralized acids having a pKa of 5 orless, wherein at least 90% of the acid groups are neutralized. Forexample, such hydrophilic polymers can comprise neutralized carboxy,sulfo, phospho, sulfinic, or phosphinic acid groups. Such neutralizedgroups can be pendant to the polymer backbones. Examples of suchhydrophilic polymer include but are not limited to, neutralizedhomopolymers or copolymers derived from (meth)acrylic acid orstyrenesulfonic acid.

It is to be understood that of the hydrophilic polymers described above,not every hydrophilic polymer may perform optimally, but that a skilledartisan would be able to use routine experimentation to obtain the besthydrophilic polymer for a desired use.

The hydrophilic polymers described above can be applied singly or asmixtures particularly in aqueous formulations (containing water ormixtures of water and water-miscible organic solvents) that may includeat least 0.1 weight %, generally from about 0.5 to about 5 weight %, andtypically from 0.8 to 2 weight %, of the hydrophilic polymers.Particularly useful compositions comprising deposition inhibitormaterials such as the hydrophilic polymers are described in copendingand commonly assigned U.S. Ser. No. 12/622,660 (noted above), that isincorporated herein by reference.

The process of making the patterned thin film of present invention canbe carried out below a maximum substrate temperature of about 600° C.,or typically below 250° C., or even at temperatures as low as roomtemperature (about 25° C.). The temperature selection generally dependson the substrate and processing parameters known in the art, once onehas the knowledge of the present invention contained herein. Thesetemperatures are well below traditional integrated circuit andsemiconductor processing temperatures, which enables the use of any of avariety of relatively inexpensive substrates, such as flexible polymericsupports. Thus, the invention enables production of relativelyinexpensive circuits containing thin film transistors with significantlyimproved performance.

In one embodiment, the present method allows one to make thin filmsemploying a system for delivery of gaseous materials to a substratesurface that can be adaptable to deposition on larger and web-basedsubstrates and capable of achieving a highly uniform thin filmdeposition at improved throughput speeds. This method optionally employsa continuous spatially dependent ALD (as opposed to pulsed or timedependent ALD) gaseous material distribution. The method of the presentinvention optionally allows operation at atmospheric or near-atmosphericpressures and is capable of operating in an unsealed or open-airenvironment. Because of the use of the deposition inhibitor materialdescribed above, the thin film is deposited only in selected areas of asubstrate.

Atomic layer deposition can be used to deposit a variety of inorganicthin films that are metals or that comprise a metal-containing compound.Such metal-containing compounds include, for example (with respect tothe Periodic Table) a Group V or Group VI anion. Such metal-containingcompound can include but are not limited to, oxides, nitrides, sulfidesor phosphides for example of zinc, aluminum, titanium, hafnium,zirconium, or indium, or combinations of these metals. Useful metalsinclude but are not limited to, copper, tungsten, aluminum, nickel,ruthenium, and rhodium.

Referring to FIG. 1, a cross-sectional side view of one embodiment of adelivery head 10 for atomic layer deposition onto a substrate 20according to the present invention is shown. Delivery head 10 has a gasinlet conduit 14 that serves as an inlet port for accepting a firstgaseous material, a gas inlet conduit 16 for an inlet port that acceptsa second gaseous material, and a gas inlet conduit 18 for an inlet portthat accepts a third gaseous material. These gases are emitted at anoutput face 36 via output channels 12, having a structural arrangementthat may include a diffuser, as described subsequently. The dashed linearrows in FIG. 1 refer to the delivery of gases to substrate 20 fromdelivery head 10. In FIG. 1, dotted line arrows X also indicate pathsfor gas exhaust (shown directed upwards in this figure) and exhaustchannels 22, in communication with an exhaust conduit 24 that providesan exhaust port. Since the exhaust gases may still contain quantities ofunreacted precursors, it may be undesirable to allow an exhaust flowpredominantly containing one reactive species to mix with onepredominantly containing another species. As such, it is recognized thatthe delivery head 10 may contain several independent exhaust ports.

In one embodiment, gas inlet conduits 14 and 16 are adapted to acceptfirst and second gases that react sequentially on the substrate surfaceto effect ALD deposition, and gas inlet conduit 18 receives a purge gasthat is inert with respect to the first and second gases. Delivery head10 is spaced a distance D from substrate 20, which may be provided on asubstrate support, as described in more detail subsequently.Reciprocating motion can be provided between substrate 20 and deliveryhead 10, either by movement of substrate 20, by movement of deliveryhead 10, or by movement of both substrate 20 and delivery head 10. Inthe particular embodiment shown in FIG. 1, substrate 20 is moved by asubstrate support 96 across output face 36 in reciprocating fashion, asindicated by the arrow A and by phantom outlines to the right and leftof substrate. It should be noted that reciprocating motion is not alwaysrequired for thin-film deposition using delivery head 10. Other types ofrelative motion between substrate 20 and delivery head 10 could also beprovided, such as movement of either substrate 20 or delivery head 10,or both, in one or more directions.

FIG. 2 is a step diagram for one embodiment of a method of the presentinvention for making a patterned thin film using a combination ofselected area deposition (SAD) and ALD. As shown in Step 100, asubstrate is supplied into the system. In Step 105, a depositioninhibitor material is deposited. The deposition inhibitor material cangenerically be any material that causes the material deposition to beinhibited. In one embodiment, the deposition inhibitor material ischosen specifically for the material to be deposited. The deposition ofthe deposition inhibitor material in Step 105 can be in a patternedmanner, such as using inkjet, flexography, gravure printing,microcontact printing, offset lithography, patch coating, screenprinting, or donor transfer. In an alternative embodiment, Step 105 canbe used to deposit a uniform layer of the deposition inhibitor materialand Step 110 can be optionally employed to form a patterned layer of thedeposition inhibitor material.

Continuing with FIG. 2, Step 120 deposits the desired thin film, forexample, by an Atomic Layer Deposition (ALD) process. Generically thisdeposition can use any suitable chemical vapor deposition equipment,such as ALD equipment, for example with a spatially dependent ALDsystem. The thin film is deposited only in the areas of the substratewhere there is no deposition inhibitor material. Depending on the use ofthe thin film, the deposition inhibitor material may remain on thesubstrate for subsequent processing or may be removed as shown in Step130 of FIG. 2.

In some embodiments, the deposition inhibitor material is characterizedby an inhibition power. Referring to FIG. 13B, the inhibition power isdefined as the thickness of a deposited layer that can form in theuninhibited areas 215 before the onset of significant deposition in theinhibited areas 210.

FIG. 3 is a step diagram of a preferred embodiment of an ALD process 120for making the thin film, in which two reactive gases are used, a firstmolecular precursor and a second molecular precursor. Gases are suppliedfrom a gas source and can be delivered to the substrate, for example,via a deposition device. Metering and valving apparatus for providinggaseous materials to the deposition device can be used.

As shown in Step 1, a continuous supply of gaseous materials for theprocess is provided for depositing a thin film of material on asubstrate. The Steps in Sequence 15 are sequentially applied. In Step 2,with respect to a given area of the substrate (referred to as thechannel area), a first molecular precursor or reactive gaseous materialis directed to flow in a first channel over the channel area of thesubstrate and reacts therewith. In Step 3 relative movement of thesubstrate and the multi-channel flows in the system occurs, which setsthe stage for Step 4, in which second channel (purge) flow with inertgas occurs over the given channel area. Then, in Step 5, relativemovement of the substrate and the multi-channel flows sets the stage forStep 6, in which the given channel area is subjected to atomic layerdeposition in which a second molecular precursor now over the givenchannel area of the substrate and reacts with the previous layer on thesubstrate to produce (theoretically) a monolayer of a desired material.A first molecular precursor is in gas form, for example, anorganometallic compound such as diethylzinc or trimethyl-aluminum. Insuch an embodiment, the second molecular precursor is also in gaseousform and can be, for example, a non-metallic oxidizing compound. Theprocess of deposition can comprise flows of gaseous materials that areorthogonal towards the substrate, transverse across the face of thesubstrate, or some combination of both types of flows. For example, thechannels comprise or are connected to a series of correspondingsubstantially parallel elongated openings in the output face of at leastone delivery head for thin film deposition. More than one delivery headmay be employed for deposition of one or more thin films.

In many forms of spatial ALD, the channels are small and in closeproximity, with a length dimension in the direction of substrate motionthat is less than 2 cm. Alternatively, the channel areas may be largeareas of gas exposure as disclosed in U.S. Patent ApplicationPublication 2007/0224348 (Dickey et al.).

In Step 7, relative movement of the substrate and the multi-channelflows then sets the stage for Step 8 in which again an inert gas isused, this time to sweep excess second molecular precursor from thegiven channel area from the previous Step 6. In Step 9, relativemovement of the substrate and the multi-channels occurs again, whichsets the stage for a repeat sequence, back to Step 2. The cycle isrepeated as many times as is necessary to establish a desired film. Inthis embodiment of the method, the steps are repeated with respect to agiven channel area of the substrate, corresponding to the area coveredby a flow channel.

Meanwhile the various channels are being supplied with the necessarygaseous materials in Step 1. Simultaneous with the sequence of box 15 inFIG. 1, other adjacent channel areas are being processed, which resultsin multiple channel flows in parallel, as indicated in overall Step 11.As indicated above, parallel flow can be either substantially orthogonalor substantially parallel to the output face of the deposition device.

The primary purpose of the second molecular precursor is to conditionthe substrate surface back toward reactivity with the first molecularprecursor. The second molecular precursor also provides material fromthe molecular gas to combine with metal at the surface, forming an oxidewith the freshly deposited zinc-containing precursor.

This particular embodiment does not need to use a vacuum purge to removea molecular precursor after applying it to the substrate. Purge stepsare expected by most researchers to be the most significantthroughput-limiting step in ALD processes.

Assuming that, for the two reactant gases in FIG. 3, AX and BY are used,for example. When the reaction gas AX flow is supplied and flowed over agiven substrate area, atoms of the reaction gas AX are chemicallyadsorbed onto a substrate, resulting in a layer of A and a surface ofligand X (associative chemisorptions) (Step 2). The remaining reactiongas AX is then purged with an inert gas (Step 4). The flow of reactiongas BY and a chemical reaction between AX (surface) and BY (gas) occur,resulting in a molecular layer of AB on the substrate (dissociativechemisorptions) (Step 6). The remaining gas BY and by-products of thereaction are purged (Step 8). The thickness of the thin film may beincreased by repeating the process cycle (steps 2-9) many times.

Because the film can be deposited one monolayer at a time it tends to beconformal and have uniform thickness.

Thin films of oxides that can be made using the method of the presentinvention include but are not limited to zinc oxide (ZnO), aluminumoxide (Al₂O₃), hafnium oxide, zirconium oxide, indium oxide, tin oxide,and others that would be readily apparent to a skilled worker. Mixedstructure oxides that can be made using the process of the presentinvention can include but are not limited to InZnO. Doped materials thatcan be made using the process of the present invention can include butare not limited to ZnO:Al, Mg_(x)Zn_(1-x)O, and LiZnO.

Thin films of metals that can be made using the method of the presentinvention include but are not limited to, copper, tungsten, aluminum,nickel, ruthenium, and rhodium. It will be apparent to the skilledartisan that alloys of two, three, or more metals may be deposited,compounds may be deposited with two, three, or more constituents, andgraded films and nano-laminates may be produced as well.

These variations are simply variants using particular embodiments of theinvention in alternating cycles. There are many other variations withinthe spirit and scope of the invention.

For various volatile zinc-containing precursors, precursor combinations,and reactants useful in ALD thin film processes, reference is made tothe Handbook of Thin Film Process Technology, Vol. 1, edited by Glockerand Shah, Institute of Physics (TOP) Publishing, Philadelphia 1995,pages B1.5:1 to B1.5:16, hereby incorporated by reference; and Handbookof Thin Film Materials, edited by Nalwa, Vol. 1, pages 103 to 159,hereby incorporated by reference, including Table V1.5.1 of the formerreference.

Although oxide substrates provide groups for ALD deposition, plasticsubstrates can be also used by suitable surface treatment.

Referring now to FIG. 4, there is shown a cross-sectional side view ofone embodiment of a delivery head 10 that can be used in the presentmethod for atomic layer deposition onto a substrate 20 according to thepresent invention. Delivery head 10 has a gas inlet port 14 foraccepting a first gaseous material, a gas inlet port 16 for accepting asecond gaseous material, and a gas inlet port 18 for accepting a thirdgaseous material. These gases are emitted at an output face 36 viaoutput channels 12, having a structural arrangement describedsubsequently. The arrows in FIG. 4 and subsequent FIGS. 6A and 6B referto the diffusive transport of the gaseous material, and not the flow,received from an output channel. In this particular embodiment, the flowis substantially directed out of the page of the figure, as describedfurther below.

In one embodiment, gas inlet ports 14 and 16 are adapted to accept firstand second gases that react sequentially on the substrate surface toeffect ALD deposition, and gas inlet port 18 receives a purge gas thatis inert with respect to the first and second gases. Delivery head 10 isspaced a distance D from substrate 20, provided on a substrate support,as described in more detail subsequently. Reciprocating motion can beprovided between substrate 20 and delivery head 10, either by movementof substrate 20, by movement of delivery head 10, or by movement of bothsubstrate 20 and delivery head 10. In the particular embodiment shown inFIG. 4, substrate 20 is moved across output face 36 in reciprocatingfashion, as indicated by the arrow R and by phantom outlines to theright and left of substrate 20 in FIG. 4. It should be noted thatreciprocating motion is not always required for thin-film depositionusing delivery head 10. Other types of relative motion between substrate20 and delivery head 10 could also be provided, such as movement ofeither substrate 20 or delivery head 10 in one or more directions, asdescribed in more detail subsequently.

The cross-sectional view of FIG. 5 shows gas flows emitted over aportion of output face 36 of delivery head 10. In this particulararrangement, each output channels 12, separated by partitions 13, is ingaseous flow communication with one of gas inlet ports 14, 16 or 18 seenin FIG. 4. Each output channel 12 delivers typically a first reactantgaseous material O, or a second reactant gaseous material M, or a thirdinert gaseous material I.

FIG. 5 shows a relatively basic or simple arrangement of gases. It isenvisioned that a plurality of non-metal deposition precursors (likematerial O) or a plurality of metal-containing precursor materials (likematerial M) may be delivered sequentially at various ports in athin-film single deposition. Alternately, a mixture of reactant gases,for example, a mixture of metal precursor materials or a mixture ofmetal and non-metal precursors may be applied at a single output channelwhen making complex thin film materials, for example, having alternatelayers of metals or having lesser amounts of dopants admixed in a metaloxide material. The inter-stream labeled I separates any reactantchannels in which the gases are likely to react with each other. Firstand second reactant gaseous materials O and M react with each other toeffect ALD deposition, but neither reactant gaseous material O nor Mreacts with inert gaseous material I. The nomenclature used in FIG. 5and following suggests some typical types of reactant gases. Forexample, first reactant gaseous material O could be an oxidizing gaseousmaterial. Second reactant gaseous material M could be an organo-metalliccompound. In an alternative embodiment, O may represent a nitrogen- orsulfur-containing gaseous material for forming nitrides and sulfides.Inert gaseous material I could be nitrogen, argon, helium, or othergases commonly used as purge gases in ALD processes. Inert gaseousmaterial I is inert with respect to first or second reactant gaseousmaterials O and M. Reaction between the first and second reactantgaseous materials would form a metal oxide or other binary compound,such as zinc oxide ZnO, in one embodiment. Reactions between more thantwo reactant gaseous materials could form other materials such as aternary compound, for example, ZnAlO.

The cross-sectional views of FIGS. 6A and 6B show, in simplifiedschematic form, the ALD coating operation performed as substrate 20passes along output face 36 of delivery head 10 when delivering reactantgaseous materials O and M. In FIG. 6A, the surface of substrate 20 firstreceives an oxidizing material from output channels 12 designated asdelivering first reactant gaseous material O. The surface of thesubstrate now contains a partially reacted form of material O, which issusceptible to reaction with material M. Then, as substrate 20 passesinto the path of the metal compound of second reactant gaseous materialM, the reaction with M takes place, forming a metallic oxide or someother thin film material that can be formed from two reactant gaseousmaterials.

As FIGS. 6A and 6B show, inert gaseous material I is provided in everyalternate output channels 12, between the flows of first and secondreactant gaseous materials O and M. Sequential output channels 12 areadjacent, that is, share a common boundary, formed by partitions 13 inthe embodiments shown. Here, output channels 12 are defined andseparated from each other by partitions 13 that extend at aperpendicular to the surface of substrate 20.

As mentioned above, in this particular embodiment, there are no vacuumchannels interspersed between the output channels 12, that is, no vacuum(exhaust) channels on either side of a channel delivering gaseousmaterials to draw out the gaseous materials around the partitions. Thisadvantageous, compact arrangement is possible because of the innovativegas flow that is used. Gas delivery arrays, in one embodiment, can applysubstantially vertical (that is, perpendicular) gas flows against thesubstrate, but then must usually draw off spent gases in the oppositevertical direction, so that exhaust openings and channels would bedesirable. A delivery head 10 that directs a gas flow (preferablysubstantially laminar in one embodiment) along the surface for eachreactant and inert gas can more easily handle spent gases and reactionby-products in a different manner, as described subsequently. Thus, inone useful embodiment, the gas flow is directed along and generallyparallel to the plane of the substrate surface. In other words, the flowof gases is substantially transverse to the plane of a substrate ratherthan perpendicular to the substrate being treated.

FIG. 7 shows a perspective view of one such embodiment of delivery head10 that can be used in the present process, from the output face 36(that is, from the underside with respect to FIGS. 4-6B). Partitions 13that define and separate the adjacent output channels 12 in thisembodiment are represented as partially cut away, to allow bettervisibility for the gas flows flowing from gas outlet ports 24. FIG. 7also shows reference x, y, z coordinate axis assignments used in thefigures of this disclosure. Output channels 12 are substantially inparallel and extend in a length direction that corresponds to the xcoordinate axis. Reciprocating motion of substrate 20, or motionrelative to substrate 20, is in the y coordinate direction, using thiscoordinate assignment.

FIG. 7 shows the gas flows F_(I), F_(O), and F_(M) for the variousgaseous materials delivered from delivery head 10 with this embodiment.Gas flows F_(I), F_(O), and F_(M) are in the x-direction, that is, alongthe length of elongated output channels 12.

The cross-sectional views of FIGS. 8A and 8B are taken orthogonally tothe cross-sections of FIGS. 4-6B and show gas flows in one directionfrom this view. Within each output channel 12, the corresponding gaseousmaterial flows from a gas output port 24, shown in phantom in the viewsof FIGS. 8A and 8B. In the embodiment of FIG. 8A, gas flow F1 directsthe gaseous material along the length of output channel 12 and acrosssubstrate 20, as was described with reference to FIG. 7. Flow F1continues past the edge of delivery head 10 in this arrangement, flowingoutward into the environment or, if desirable, to a gas collectionmanifold (not shown). FIG. 8B shows an alternative embodiment for gasflow F2 in which output channel 12 also provides an exhaust port 26 forredirection or drawing off of the gas flow. Although unidirectionalflows are useful, some degree of mixing can occur and even may bebeneficial to some extent, depending on the flow rates and othercircumstances involved in a particular application.

A particular delivery head 10 may use output channels 12 configuredusing any one of the gas flow configurations or combinations thereof,either the F1 flow of FIG. 8A, the F2 flow of FIG. 8B, or some othervariation in which gaseous material is directed to flow across substrate20 along output channel 12, for example in a substantially laminar orsmooth fashion with controlled mixing. In one embodiment, one or moreexhaust ports 26 are provided for each output channel 12 that delivers areactant gaseous material. For example, referring to FIG. 7, outputchannels 12 for first and second reactant gaseous materials, labeled Oand M, are configured with exhaust ports 26 to vent or draw off thereactant substances, following the pattern of flow F2 (FIG. 8B). Thisallows some recycling of materials and prevents undesirable mixing andreaction near the end of the manifold. Output channels 12 for inertgaseous material, labeled I, do not use exhaust ports 26 and thus followthe pattern of flow F1 (FIG. 8A). Although laminar flows are useful insome embodiments, some degree of mixing can occur and even may bebeneficial to some extent, depending on the flow rates and othercircumstances involved in a particular application.

Exhaust port 26 is not a vacuum port, in the conventional sense, but issimply provided to draw off the gaseous flow in its corresponding outputchannel 12, thus facilitating a uniform gas flow pattern within thechannel. A negative draw, just slightly less than the opposite of thegas pressure at gas output port 24, can help to facilitate an orderlygas flow. The negative draw can, for example, operate at a pressure ofbetween 0.9 and 1.0 atmosphere, whereas a typical vacuum is, forexample, below 0.1 atmosphere. An optional baffle 58, as shown in dottedoutline in FIG. 8B, may be provided to redirect the flow pattern intoexhaust port 26.

Because no gas flow around partition 13 to a vacuum exhaust is needed,output face 36 can be positioned very closely, to within about 1 mil(approximately 0.025 mm) of the substrate surface. By comparison, anearlier approach such as that described in the U.S. Pat. No. 6,821,563(Yudovsky) required gas flow around the edges of channel sidewalls andwas thus limited to 0.5 mm or greater distance to the substrate surface.Positioning the delivery head 10 closer to the substrate surface isdesired in the present invention. In one embodiment, distance D from thesurface of the substrate can be 0.4 mm or less, or within 0.3 mm,typically within 0.25 mm of the output face of the deposition device orthe bottom of the guide walls that provide the flow channels.

In order to provide smooth flow along the length of output channel 12,gas output port 24 may be inclined at an angle away from normal, asindicated in FIGS. 8A and 8B. Optionally, some type of gas flowredirecting structure may also be employed to redirect a downward flowfrom gas output port 24 so that it forms a gas flow that runssubstantially in parallel to output face 36.

As was particularly described with reference to FIGS. 6A and 6B,delivery head 10 requires movement relative to the surface of substrate20 in order to perform its deposition function. This relative movementcan be obtained in a number of ways, including movement of either orboth delivery head 10 and substrate 20, such as by movement of a processthat provides a substrate support. Movement can be oscillating orreciprocating or could be continuous movement, depending on how manydeposition cycles are needed. Rotation of a substrate can also be used,particularly in a batch process, although continuous processes arepreferred.

Typically, ALD requires multiple deposition cycles, building up acontrolled film depth with each cycle. Using the nomenclature for typesof gaseous materials given earlier, a single cycle can, for example in asimple design, provide one application of first reactant gaseousmaterial O and one application of second reactant gaseous material M.

The distance between output channels for O and M reactant gaseousmaterials determines the needed distance for reciprocating movement tocomplete each cycle. For an example, delivery head 10, having a nominalchannel width of 0.034 inches (0.086 cm) in width W for each outputchannel 12 and reciprocating motion (along the y axis as used herein) ofat least 0.20 inches would be required. For this example, an area ofsubstrate 20 would be exposed to both first reactant gaseous material Oand second reactant gaseous material M with movement over this distance.In some cases, consideration for uniformity may require a measure ofrandomness to the amount of reciprocating motion in each cycle, such asto reduce edge effects or build-up along the extremes of reciprocationtravel.

Delivery head 10 may have only enough output channels 12 to provide asingle cycle. Alternately, delivery head 10 may have an arrangement ofmultiple cycles, enabling it to cover a larger deposition area orenabling its reciprocating motion over a distance that allows two ormore deposition cycles in one traversal of the reciprocating motiondistance.

In one embodiment, a given area of the substrate is exposed to a gasflow in a channel for less than 500 milliseconds, preferably less than100 milliseconds. For example, the temperature of the substrate duringdeposition is under 600° C. or typically under 250° C.

For example, in one particular application, it was found that each O-Mcycle formed a layer of one atomic diameter over about ¼ of the treatedsurface. Thus, four cycles, in this case, are needed to form a uniformlayer of 1 atomic diameter over the treated surface. Similarly, to forma uniform layer of 10 atomic diameters in this case, then, 40 cycleswould be required.

An advantage of the reciprocating motion used for a delivery head 10used in one embodiment of the present process is that it allowsdeposition onto a substrate 20 whose area exceeds the area of outputface 36. FIG. 9 schematically shows how this broader area coverage canbe affected using reciprocating motion along the y axis as shown byarrow R and also movement orthogonal or transverse to the reciprocatingmotion, relative to the x axis. Again, it must be emphasized that motionin either the x or y direction, as shown in FIG. 9, can be effectedeither by movement of delivery head 10, or by movement of substrate 20provided with a substrate support 74 that provides movement, or bymovement of both delivery head 10 and substrate 20.

In FIG. 9 the relative motion of the delivery head 10 and the substrate20 are perpendicular to each other. It is also possible to have thisrelative motion in parallel. In this case, the relative motion needs tohave a nonzero frequency component that represents the oscillation and azero frequency component that represents the displacement of thesubstrate 20. This combination can be achieved by: an oscillationcombined with displacement of the delivery head 10 over a fixedsubstrate; an oscillation combined with displacement of the substrate 20relative to a fixed substrate delivery head 10; or any combinationswherein the oscillation and fixed motion are provided by movements ofboth the substrate 20 and the delivery head 10.

In one embodiment, ALD can be performed at or near atmospheric pressureand over a broad range of ambient and substrate temperatures, forexample at a temperature of under 300° C. Generally, a relatively cleanenvironment is needed to minimize the likelihood of contamination.However, full “clean room” conditions or an inert gas-filled enclosurewould not be required for obtaining good performance when using someembodiments of the method of the present invention.

FIG. 10 shows an Atomic Layer Deposition (ALD) 60 process, for making athin film, having a chamber 50 for providing a relativelywell-controlled and contaminant-free environment. Gas supplies 28 a, 28b, and 28 c provide the first, second, and third gaseous materials todelivery head 10 through supply lines 32. The optional use of flexiblesupply lines 32 facilitates ease of movement of delivery head 10. Forsimplicity, an optional vacuum vapor recovery process and other supportcomponents are not shown in FIG. 10 but could also be used. A transportsubsystem 54 provides a substrate support that conveys substrate 20along output face 36 of delivery head 10, providing movement in the xdirection, using the coordinate axis system employed in the presentdisclosure. Motion control, as well as overall control of valves andother supporting components, can be provided by a control logicprocessor 56, such as a computer or dedicated microprocessor assembly,for example. In the arrangement of FIG. 10, control logic processor 56controls an actuator 30 for providing reciprocating motion to deliveryhead 10 and also controls a transport motor 52 of transport subsystem54.

FIG. 11 shows an Atomic Layer Deposition (ALD) system 70 for depositinga thin film in a web arrangement, using a stationary delivery head 10 inwhich the flow patterns are oriented orthogonally to the configurationof FIG. 10. In this arrangement, motion of web conveyor 62 provides themovement needed for ALD deposition. Reciprocating motion could also beused in this environment, such as by repeatedly reversing the directionof rotation of a web roller to move web substrate 66 forward andbackwards relative to delivery head 10. Reciprocation motion can also beobtained by allowing a reciprocating motion of the delivery head 10across an arc whose axis coincides with the roller axis, while the websubstrate 66 is moved in a constant motion. In another embodiment atleast a portion of delivery head 10 has an output face 36 having anamount of curvature (not shown), which might be advantageous for someweb coating applications. Convex or concave curvature could be provided.

Optionally, the present method can be accomplished with other apparatusor systems described in more detail in U.S. Pat. Nos. 7,413,982 and7,456,429 and U.S. Patent Application Publications 2008/0166884 and2009/0130858 (all noted above and incorporated by reference in theirentirety).

In the embodiments in the latter three publications, a delivery devicehaving an output face for providing gaseous materials for thin-filmmaterial deposition onto a substrate comprises elongated emissivechannels in at least one group of elongated emissive channels, of thethree groups of elongated emissive channels (namely, at least one groupof: (i) one or more first elongated emissive channels, (ii) one or moresecond elongated channels, and (iii) a plurality of third elongatedchannels) that is capable of directing a flow, respectively, of at leastone of the first gaseous material, second gaseous material, and thethird gaseous material substantially orthogonally with respect to theoutput face of the delivery device, which flow of gaseous material iscapable of being provided, either directly or indirectly from each ofthe elongated emissive channels in the at least one group, substantiallyorthogonally to the surface of the substrate.

In one embodiment, apertured plates are disposed substantially inparallel to the output face, and apertures on at least one of theapertured plates form the first, second, and third elongated emissivechannels. In an alternative embodiment, the apertured plates aresubstantially perpendicularly disposed with respect to the output face.

In one such embodiment, the deposition device comprises exhaustchannels, for example, a delivery device for thin-film materialdeposition onto a substrate comprising: (a) a plurality of inlet portscomprising at least a first inlet port, a second inlet port, and a thirdinlet port capable of receiving a common supply for a first reactivegaseous material, a second reactive gaseous material, and a third (inertpurge) gaseous material, respectively, (b) at least one exhaust portcapable of receiving exhaust gas from thin-film material deposition andat least two elongated exhaust channels, each of the elongated exhaustchannels capable of gaseous fluid communication with the at least oneexhaust port, and (c) at least three pluralities of elongated outputchannels, (i) a first plurality of first elongated output channels, (ii)a second plurality of second elongated output channels, and (iii) athird plurality of third elongated output channels, each of the first,second, and third elongated output channels capable of gaseous fluidcommunication, respectively, with one of the corresponding first inletport, second inlet port, and third inlet port; wherein each of thefirst, second, and third elongated output channels and each of theelongated exhaust channels extend in a length direction substantially inparallel; wherein each first elongated output channel is separated on atleast one elongated side thereof from a nearest second elongated outputchannel by a relatively nearer elongated exhaust channel and arelatively less near third elongated output channel; and wherein eachfirst elongated emissive channel and each second elongated emissivechannel is situated between relatively nearer elongated exhaust channelsand between relatively less nearer elongated emissive channels.

Further embodiments can comprise a gas diffuser associated with at leastone group of the three groups of elongated emissive channels such thatat least one of the first, second, and third gaseous material,respectively, is capable of passing through the gas diffuser prior todelivery from the delivery device to the substrate, during thin-filmmaterial deposition onto the substrate, and wherein the gas diffusermaintains flow isolation of the at least one of first, second, and thirdgaseous material downstream from each of the elongated emissive channelsin the at least one group of elongated emissive channels.

In one embodiment, such a gas diffuser is capable of providing afriction factor for gaseous material passing there through that isgreater than 1×10², thereby providing back pressure and promotingequalization of pressure where the flow of the at least one first,second and third gaseous material exits the delivery device. In oneembodiment of the invention, the gas diffuser comprises a porousmaterial through which the at least one of the first, second, and thirdgaseous material passes. In a second embodiment of the invention, thegas diffuser comprises a mechanically formed assembly comprising atleast two elements comprising interconnected passages, for example, inwhich nozzles are connected to a flow path provided by a thin spacebetween parallel surface areas in the two elements.

In one embodiment, the one or more of the gas flows from the depositiondevices provides a pressure that at least contributes to the separationof the surface of the substrate from the face of the delivery head,thereby providing a “floating head” or “air bearing” type depositionhead, which can help to stabilize the gas flows and limit intermixing ofthe gas flows.

The method of the present invention is advantaged in its capability toperform deposition onto a substrate over a broad range of temperatures,including room or near-room temperature in some embodiments. The methodcan operate in a vacuum environment, but is particularly well suited foroperation at or near atmospheric pressure.

It should be recognized that any ALD equipment may be used withdeposition inhibitor materials. Other spatial ALD processes, such asthose as described by previously referenced publications by Yudovsky andDickey et al. and by U.S. Pat. No. 4,413,022 (Suntola et al.) are alsouseful with the present invention, and as such represent alternateembodiments herein. Traditional chamber based or temporal ALD processesmay also be employed with the hydrophilic polymer deposition inhibitormaterials of the present invention.

It is the goal of the present invention to provide a patterned thin filmthat is not only deposited via an ALD or CVD process, but simultaneouslypatterned using selective area deposition (SAD) materials and processes.As described above, SAD processes use a deposition inhibitor compound inorder to inhibit the ALD growth of the thin film in the non-selectedareas. This process can be better understood with reference to FIGS. 12Athrough 12E. FIG. 12A shows substrate 200 prior to the application ofthe deposition inhibitor material 210. Although the substrate 200 isillustrated as a bare substrate, one skilled in the art should recognizethat substrate 200 might contain layers of materials, either patternedor unpatterned, to serve any purpose electrical, optical, or mechanical,as desired. FIG. 12B shows substrate 200 after a uniform deposition ofdeposition inhibitor material 210. FIG. 12C illustrates substrate 200after the step of patterning the deposition inhibitor material 210 intodeposition mask 225. The patterning can be done by any method known inthe art, including photolithography using either positive or negativeacting photoresists, laser ablation, or other subtractive processes. Asshown, deposition mask 225 contains areas of deposition inhibitormaterial 210 and areas of substrate for deposition 215. FIG. 12Dillustrates substrate 200 after the step of atomic layer deposition ofthe desired thin film material. As shown, thin film material 220 is onlydeposited on the substrate 200 where there was no deposition inhibitormaterial 210. The thin film material 220 does not form any appreciablethin film over deposition inhibitor material 210. FIG. 12E illustrates apatterned thin film material 220 after removing the deposition inhibitormaterial 210. It should be understood by one skilled in the art, that insome instances it would not be necessary to remove the depositioninhibitor material 210.

FIGS. 13A, 13C, and 13D should be understood with respect to thedescriptions of FIGS. 12A, 12D, and 12E respectively. FIG. 13Billustrates a deposition mask 225 formed by patterned deposition of thedeposition inhibitor material 210. Patterned deposition may be doneusing any additive printing method including, but not limited to inkjet,gravure, flexography, patch coating, screen printing, donor transfer,microcontact printing, or offset lithography.

The following Example is provided to illustrate the practice of thisinvention but it is not meant to be limiting in any manner.

The following procedure was used in the evaluation of the samples:

Measurement of Inhibition Power:

When a substrate surface containing no deposition inhibitor is subjectedto ALD deposition, film growth occurs immediately upon commencement ofthe ALD exposure cycles. Alternatively, when a deposition inhibitor ispresent on a surface, initial application of ALD exposure cycles leadsto no film growth. However, most deposition inhibitors do not inhibitperfectly. Thus, after continued application of ALD exposure cycles,there will be an onset of film growth on surfaces containing adeposition inhibitor. As defined above, the inhibition power of aselective area inhibitor is defined as the amount of film growth thatwould have occurred in the absence of deposition inhibitor prior to theonset of growth on a substrate that is coated with a depositioninhibitor. A higher inhibition power indicates a more effectivedeposition inhibitor.

In a typical process step employing a patterned selective areainhibitor, it is desired to grow a certain film thickness in the areasnot containing deposition inhibitor. At the same time, it is desiredthat little or no deposition occur in regions containing the depositioninhibitor. Thus, the inhibition power can then be thought of as themaximum amount of film growth allowable when using a particulardeposition inhibitor to pattern deposition.

To measure the inhibition, a glass substrate was spin coated with adeposition inhibitor solution and then baked in air to ensure completeremoval of solvent. The same solution can be coated and baked on a baresilicon wafer in order to test that sample for film thickness usingellipsometry. The glass substrate for the inhibition test was thensubjected to ALD growth using a gas bearing ALD coating head asdescribed in U.S. Patent Application Publication 2009/0130858 (Levy).The coating head contained regions for a metal precursor, and oxygenprecursor, and inert purge or separator gases.

To test deposition inhibitors, zinc oxide film growth at 200° C. wasused. This deposition employed diethyl zinc (DEZ) as the zinc precursorand water as the oxygen precursor. During this deposition, the partialpressure of DEZ in the metal channels was 100 mtorr, while the partialpressure of water in the oxygen source channels was 50 mtorr. The inertgas and the carrier gases were nitrogen. The substrate speed yielded achannel residence time (thus ALD exposure time) of 63 msec (the same forall precursor and inert streams). At these conditions, an uninhibitedsubstrate will experience a film growth of about 1.63 Å/cycle.

Film thickness of the resulting ZnO layers on top of the depositioninhibitor was determined by light absorption at 355 nm. The absorptionwas then be converted to thickness by a calibration. Samples containinga deposition inhibitor were subjected to ALD deposition for 50 cycles ata time and then characterized for thickness on the inhibitor. Once theonset of growth occurred, the number of cycles required to produce afilm thickness of 100 Å on the deposition inhibitor surface wasinterpolated from the data. The thickness of a control containing nodeposition inhibitor was then calculated for the same number of cyclesusing the above growth per cycle. The inhibition power of the depositioninhibitor was therefore the calculated growth that would have occurredon an uninhibited substrate minus the 100 A allowance for film that hadalready grown on the deposition inhibitor.

In any test, the maximum number of ALD cycles tested was 1200, yieldinga ZnO film on an uninhibited surface of approximately 2000 Å. Thus,samples that showed no growth at this time have a minimum inhibitionpower of 2000 Å.

Use of Hydrophilic Neutralized Polymers

Polymers containing neutralizable acid groups are shown below in TABLEI. It also shows the stock polymer solutions that were created, each ofwhich was 1% in water. The pH of each solution is shown. An (“a”) in thepH column indicates that the polymer solution was adjusted to the shownpH, while an (“n”) indicates that the pH of the polymer solution wasused without any pH adjustment (pH adjustment was done with a solutionof sodium hydroxide).

TABLE I Deposition Inhibitor Polymer Molecular WeightPoly(styrenesulfonic acid) 70,000 Poly(styrenesulfonic acid), 1,000,000sodium salt Poly(acrylic acid) 90,000

Titratable acid measurements for each polymer were obtained bydissolving 1 g of each polymer in 99 g of water. A solution containingsodium hydroxide was pumped into the stirred polymer solution at a rateof 1.3 ml per minute, during which time the pH of the solution wasmonitored. The time required to achieve a pH of 10 was recorded,yielding the total amount of base solution required to neutralize anyacid groups present in the system. Depending upon the concentration ofthe base solution used, the total volume of required base solution wasconverted to determine the acid content of the polymer. For polymersolutions set to a specific starting pH, the titration data from theexperiments were also used to calculate the equivalents of base requiredto bring the solution from its starting pH to a pH of 10. For each case,the completely protonated polymer, poly(acrylic acid) orpoly(styrenesulfonic acid), is considered to have a neutralization of0%. For neutralized samples, the percent of neutralization is consideredto be the equivalents per gram polymer of the sample divided by theequivalents per gram of the completely protonated versions. Themilli-equivalents (meq) of acid per gram of polymer and the percentneutralization are listed below in TABLE II. Polymer stock solutions C-1and C-2 were outside the present invention while I-1 through I-4 werewithin the present invention.

TABLE II Titratable Stock Deposition Inhibitor Acid % solutions PolymerpH (meq/g) Neutralization C-1 Poly(styrenesulfonic 1.4 (n) 6.5 0 acid)I-1 Poly(styrenesulfonic 6.5 (n) 0.047 99 acid), sodium salt C-2Poly(acrylic acid) 3.05 (n) 13.09 0 I-2 Poly(acrylic acid) 7.0 (a) 2.1584 I-3 Poly(acrylic acid) 8.0 (a) 0.46 96 I-4 Poly(acrylic acid) 9.0 (a)0.13 99

Coating solutions were made up from the stock solutions as shown belowin TABLE III. The concentration of each solution was chosen to give afinal thickness of approximately 80 Å during spin coating at 3000 rpm.After spin coating, the samples were baked at 180° C. in air to removethe water. TABLE III also shows the deposition inhibition results ofthese polymers, including the number of ALD cycles required to achieve100 Å of deposition on top of the deposition inhibitor and thecorresponding inhibition power.

TABLE III Cycles Stock to Inhibition Sample Solution ConcentrationThickness 100 Å Power (Å) C-1 CS-1 0.50% 88 72 17 I-1 IS-1 0.34%78 >1200 >2000 C-2 CS-2 0.50% 79 65 6 I-2 IS-2 0.50% Est. 80 247 303 I-3IS-3 0.50% Est. 80 321 424 I-4 IS-4 0.50% Est. 80 327 434

As can be seen from the data in TABLE III, the polymers that werecompletely protonated, C-1 and C-2 showed rapid growth of ZnO and thusvery low and not useful inhibition power. On the other hand, thepolymers with a higher degree of acid neutralization show improvedresults. For poly(acrylic acid) at a neutralization of 84% (Sample I-2)showed a fairly useful inhibition power. The other samples with higheracid neutralization (I-1, I-3, and I-4) showed very useful inhibitionpower.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

1. An electronic device having a substrate and having thereon: adeposited pattern of a composition comprising a deposition inhibitormaterial, and a deposited inorganic thin film disposed only in selectedareas of the substrate where the composition comprising a depositioninhibitor material is absent, wherein the deposition inhibitor materialis a hydrophilic polymer that is a neutralized acid having a pKa of 5 orless, wherein at least 90% of the acid groups are neutralized.
 2. Thedevice of claim 1 wherein the hydrophilic polymer comprises neutralizedcarboxy, sulfo, phospho, sulfinic, or phosphinic acid groups.
 3. Thedevice of claim 1 wherein the hydrophilic polymer is a neutralizedhomopolymer or copolymer derived from (meth)acrylic acid orstyrenesulfonic acid.
 4. The device of claim 1 that is an integratedcircuit, active-matrix display, solar cell, active-matrix imager,sensor, or an rf label.
 5. The device of claim 1 wherein the hydrophilicpolymer comprises neutralized carboxy or sulfo groups.
 6. The device ofclaim 1 wherein the hydrophilic polymer comprises recurring units havingneutralized carboxy, sulfo, phospho, sulfinic, or phosphinic acid groupsthat are pendant to the polymer backbone.
 7. The device of claim 1wherein the hydrophilic polymer satisfies both of the following tests:a) it is soluble to at least 1% by weight in a solution containing atleast 50 weight % water as measured at 40° C., and b) it provides aninhibition power of at least 200 Å to deposition of zinc oxide by an ALDprocess.
 8. The device of claim 1 wherein the inorganic thin film iseither a metal or a metal containing compound.
 9. The device of claim 8wherein the metal-containing compound contains a group V or group VIanion, or it is an oxide, nitride, sulfide, or phosphide, or acombination thereof.
 10. The device of claim 1 wherein the inorganicthin film contains zinc oxide.
 11. The device of claim 8 whereininorganic thin film contains zinc, aluminum, hafnium, zirconium, orindium, or any combination of these metals.
 12. The device of claim 1wherein the inorganic thin film contains copper, tungsten, aluminum,nickel, ruthenium, or rhodium.